Create pattern with octave range 4-6, the high freq notes are important. Mention freq knob is at 100% on the patch picture, if your's is lower go to octave range 5-7, higher notes play a key role here.

https://www.youtube.com/watch?v=3rkpjgkNizA

Plug patch cable in osc fm input. play pattern, then pinch other end of patch cable between your fingers for instant FM.
Touchh only the tip of the patch cable for heavy FM, touch tip+under the black insulator the whole metal part for subtle FM.

Higher notes will become biting muted FM dubstep like percussive sounds, while lower notes will not that much affected.
Modify decay, cutoff for harsher effect. Add accent and especially racheting for higher notes.